Baatrup G, Jonsson H, Sjöholm A, Sturfelt G, Svehag S E
Institute of Medical Microbiology, University of Odense, Denmark.
J Clin Lab Immunol. 1988 Jun;26(2):73-9.
We describe an ELISA for assessment of complement function based on the capacity of serum to support fixation of complement components to solid phase immune complexes (IC). Microplates were coated with aggregated bovine serum albumin (BSA) followed by rabbit anti-BSA IgG. The solid phase IC were reacted with human serum. The uptake of C3b, C4b and properdin was measured using biotinylated F(ab)2 antibodies to each of the proteins, avidin alkaline phosphatase, and paranitrophenyl phosphate. Serial samples obtained from 15 patients with systemic lupus erythematosus were investigated. Out of 72 sera, 24 showed a reduced capacity to support incorporation of C4b into solid phase IC. Thirty-one of the sera showed low C3b binding and 59 of the sera a reduced uptake of properdin. The incorporation into solid phase IC of C3b and C4b as well as of C3b and properdin were closely correlated at high disease activity. In general, patients with severe disease manifestations showed low values in the uptake assays. Judging from the results obtained by analysis of serial samples, the uptake of C3b, C4b and properdin, complement mediated solubilization of fluid phase IC and the concentrations of C1q binding IC were useful indicators of disease activity in the patients. The concentrations of circulating C4, C3 and properdin varied less consistently according to disease activity. The concentrations of serum properdin were never found to be low, which was in contrast to the finding of reduced properdin uptake by solid phase IC in most of the samples.
我们描述了一种基于血清支持补体成分固定于固相免疫复合物（IC）能力的补体功能评估酶联免疫吸附测定（ELISA）。微孔板先用聚集的牛血清白蛋白（BSA）包被，然后用兔抗BSA IgG包被。固相IC与人血清反应。使用针对每种蛋白质的生物素化F(ab)2抗体、抗生物素蛋白碱性磷酸酶和对硝基苯磷酸来测量C3b、C4b和备解素的摄取。对15例系统性红斑狼疮患者获取的系列样本进行了研究。在72份血清中，24份显示支持C4b掺入固相IC的能力降低。31份血清显示C3b结合能力低，59份血清显示备解素摄取减少。在疾病活动度高时，C3b和C4b以及C3b和备解素掺入固相IC的情况密切相关。一般来说，有严重疾病表现的患者在摄取测定中值较低。从系列样本分析获得的结果判断，C3b、C4b和备解素的摄取、补体介导的液相IC溶解以及C1q结合IC的浓度是患者疾病活动度的有用指标。循环中的C4、C3和备解素浓度根据疾病活动度的变化不太一致。从未发现血清备解素浓度低，这与大多数样本中固相IC对备解素摄取减少的发现相反。
